Method of and apparatus for operating synchronous telegraph systems



Mann 6, 1923.

G. R. BENJAIVHN METHOD OF ANDAPPARATUS FOR OPERATING SYNCHRONOUS TELEGRAPH SYSTEMS Original Filed Aug.

E GeoQye/Q. Beryhmiw I IIHI (Jud ' 4 O 's'ulting Patented Mar. b, 1923.

iane UNl'l'iilE STATES PATENT @FFHQEZ.

GEOBGE R-Q BENJAMIN, F JERSEY CITY, NEW JERSEY, ASSIGNOR TO THE WESTERN UNION TELEGRAPH COMPANY, 015 DIE-XV YORK, N. Y., A CORPORATION OF NEW i YORK.

METHOD OF AND APPARATUS FOR. OPERATING SYNCHRONOUS TELEGRAPH SYSTEMS.

Application filed August 8, 1919,

To all whom it may concern:

Be it known that I, GEORGE R. BENJAMIN,

a citizen of the United States, residing at Jersey City, in the countyof Hudson and 5 State of New Jersey, have invented certain new and useful Improvements in Methods of and Apparatus for Operating Synchronous Telegraph Systems, of which the following is a specification.

This invention relates to automatic cable transmitters and is particularly intended for use in synchronous printing telegraph systems.

Owing to the large static capacity of an ocean cable it is desirable to ground it as frequently as possible to reduce the static charge and for the ble to avoid a succession of impulses of like sign or polarity. I attain these advantages by grounding the cable between successive impulses and by suppressing succeeding impulses of like polarity or sign, the trans mitted impulses always being of reversed polarity.

The main purpose of my invention is to provide means at the cable transmitting end which will automatically suppress an impulse which succeeds one of like polarity and means at the cable receiving end which will automatically introduce or supply the suppressed impulses to the translator nism or recording apparatus. In the particular system llQI'GlIldBSCIlbQCl each telegraph character consists of five impulses, the $35 necessary distinctions between the several characters being obtained by causing one or more of the current impulses to be of opposite sign, direction or polarity from the other impulses of that character; the rereversals of current sign affording the number of permutations necessary for the distinction of the several letters of the alphabet, punctuation signs and special signals for the operation of the various paratus. I

Telegraph systems such as that in connec tion with which m'y'inventionis herein illustrated and described, comprise two-or more distributers or commutators with means for maintaining synchronisin. The type of automatic tape-controlled transmitter employed is shown in my prior U. S. Patent No.

Serial No. 316,180. Renewed November 10, 1922.

same reason it is desi-ramechaparts of the transmitting and receiving ap- 1,298,:l-t0, dated Ivlarch 25, 1919,

Serial No. 600,187.

while the distributors, and method of correcting, locating and maintaining s nchronous phase relations between two cistributers at distant stations is disclosed in U. S. Patent No. 1,253,889, granted to Bothermel, January 15, 1918 and need not be further described herein. 7

F or the purpose of clearly disclosing my invention 1 shall refer to the accompanying drawings in which Figure 1 is a diagram matic illustration of the apparatus employed at the transmitting and receiving stations of a cable and embodying one form of my invention; and Figs. 2 and 2-3 illustrate short pieces of transmitting tape perforated in accordance with certain signal characters and showing also the manner in which succeeding impulses of like sign or polarity are suppressed.

The apparatus at the transmitting or sending station S, comprises essentially the transmitter T, and distributor D with the interposed overlap transmitting relay 0 T and overlap relays O R, together with the sending relay S R and cable transmitting relays T R.

The apparatus at the receivin station E comprises essentiall the cable relay G R, with its associated line relay L R, the distributor D and the recording apparatus in cluding the selecting relays, starting magnet and clear-out relay which are connected to the circuits and mechanism of the printing mechanism in the manner well understood.

For the sake of clearness I have illustrated only the transmitting apparatus at the station S at one end of the cable and only a receiving apparatus at the station R at the other end of the cable, but it is understood that it is common practice to duplex the cable operation so that each station may simultaneously send and receive messages. The requirements for this purpose would be to substitute the sending apparatus shown at station S for the cable key K at station E,

' and associate a receivin a )aratus shown at station R with the cable relay C R at station S.

The distributers or commutators D, D

comprise a series of concentric segmented and solid rings R, R R etc, rotarily mounted and having adj utably mounted stationary brushes B R, B R,etc.,' the disks or shafts carrying the rings being maintained in sychronism and proper phase relation at the different stations in accordance with the Rothermel patent above mentioned. For

the sake of clearness the distributer rings are developed as straight bands. These distributershave been described in various patents of The'Western Union Telegraph Com- :pany, mentioned and need not be further described.

In illustrating the transmitter T, which is of the type shown in my prior patent mentioned, I have deemed it sufficient to indi 'cate the circuit connections, omitting the perforated tape and tape feed mechanism. The movable tongues t normally rest against the back contacts which are connected to the negative pole of battery 10,

the front contacts being connected to the plus or positive pole of battery 12. The

tongues 1, 2- and 8 are directly connected to the corresponding segments of ring R of distributer'D, while tongues 4 and 5 are con nected to the armatures of overlap transmitter relay 0 T. When the brushes B R pass over the segments 2 of ring R the of the transmitter T. If the armatures' 7 swing to the right they will impress a positive charge on the segments 4-, 5 of the ring R from the battery .20, while they will impress negative charges thereon if they swing sponding to the first two impulses.

to the left from the battery 21. At the same time holding circuits are closed through the coils 23, 23', the holding currents being made very weak by including resistances 24, 2a.

Referring to Fig. 2, it will be observed f rot n the impulse diagrams I) that the letter A consists of two plus or positive im pulses followed by three minus or negative impulses, The perforations for the letter A in the sending tape S T shown at (4 consists of only two perforations corre- These permit the pins or feelers attached to the tongues 1, 2 of the transmitterT to pass through, thereby causing said tongues to swing over against the front contacts con- -nected to the plus battery 12. -As there are no perforations in the tape for the other three pins, the tongues 23, 4 and 5 remain against their back stops which are connected to negative battery 10. As a consequence Whenthe tape S T is moved over the transmitter pins with the two perforations indi and tongues 3, 4 and 5 will remain including Patent No. 1,253,889 above cated for the letter A, tongues .1 and 2 will be charged positively from battery 12 and be charged negatively from battery 10. The charges from tongues 1, 2 and 3 are directly impressed upon segments 1, 2 and 3 respectively of ring R of the distributer, while the charges on tongues 4: and 5 are impressed on the two armatures of overlap transmitter relay 0 T.

As the brushes pass over the rings of the distributer the brushes B R first connect segment 10f ring R with ringR- thereby transmitting the plus charge previously impressed on this segment through conductor to the coils of sending relay S R. As

this is. a positive current the armature will swing over against the right hand contact, thereby sending a positive charge into condenser C from battery 28 and energizing the plus magnet of transmitting relay T R. The armature of the latter isdrawn against its front contact, thereby sending a positive impulse fromthe main battery 30 into the cable. The capacity of the condenser C may be adjusted so thatthe charging current will continue for the fulltime the brush is passing acrossthe segment 1.: As soon as the condenser is fully charged, so that the charging current ceases to flow, the armature of the relay T R will be drawn against its back stop by its retractile spring, thereby grounding the cable through the armatures of the two magnets of the relay T R and the bridge wire connectinw the back stops.

During the Tatter part of the movement; of the brushes B R across segment 1 of ring R, thebrushes B R connect the segments 2 of ring T1 to solid ring R, thereby energizing the coil of relay 0 T from battery 1 1. The attraction of the armatu-res connects the tongues 1 and 5 of the transmitter T to the coils 18 and 18 of overlap relay O R and as the charging currents on both of these tongues is negative, the armatures 19 and 19 will swing against the left hand contacts thereby impressing negative charges upon the segments 1 andv 50f ring R from battery 21. The Var-matures will be held in the left hand position by the small current flowing through the holding coils 23, 23, these coils being weaker than the actuating coils 18, 18". y

. As the brush B Rmoves onto the segment 2 of ring R a positive impulse will again flow through the sending relay S R, causing its armature to swing to the right and again connect the plus battery 28 to the condenser C. Inasmuch, however, as the condenser was fully charged with a positive current while the brush was passing over segment 1, 110 further charging current will flowand hence the plusmagnet of transmitting relayT R will not be energized. Since no current impulse is transmitted to the cable the effect of the second or succeeding positive impulse ofthe letter A is suppressed and the cable remains grounded. will be evident that a succeeding impulse of like sign is suppressed in the same manner, even though it is the first impulse of a letter, if it follows an impulse of the same sign in the preceding letter or character.

lVhen the brush B R passes onto segment 3 of ring R the negative current impulse from battery 10 through tongue 3 of transmitter T is sent through relay 5 R, causing its armature to swing to the left and connect condenser C to the negative pole of battery 28, a charging current flowing because it is in the same direction as the discharge from the previous charge. The minus magnet of relay T B being thus 'energized, draws its armature against its front contact and thereby causes a negative current impulse to flow into the .cable from the battery 30. As the condenser C is fully charged negatively, the negative charges on the following segments 4 and 5 which energize the relay S R as the brushes B B pass over these segments, will not cause any further charging current to flow into the condenser and consequently these two negative impulses succeeding the negative impulse on segment 3,wil1"be suppressed. It will be observed, therefore, that only the first positive charge on segment 1 and the first negative charge on segment 3 caused corresponding current impulses to lietransmitted into the cable, the positive charge on. segment 2 and the negative charges on segments 4 and 5 causing no currents to flow into the condenser and the corresponding impulses being therefore suppressed. This is shown graphically at; Z in Figs. 2and Inasmuch as an interval oftime must be provlded torthe operation of the tape feeding mechanism and in order that the current charges shall be set up: on the first segment of the ring R before theibrushes leave the segment 5-and pass again upon the segment "1, provision is made for moving the tapeforwardto the next character andithereby setting up the combination of positive and negative charges of the succeedingletter on the tongues of the transmitter and likewise on the first three segments of ring R while the brushes are still passing over-segments 4 and 5; in other words, the current charges of the preceding letteron segments 4 and 5 are allowed to remain and overlap the setting up of the charges of the succeeding letter on the segments'l, 2 and 3.

To accomplish this purpose, as the brush B R movesonto segment i of ring R brushes B R connect segmentsd of ring R with grounded ring R thereby energizing the magnet T M of the transmitter which actuates the feeding device, withdrawing the pins from the tape and movingit forward, the

ceiving station.

Referring now to the apparatus at the re ceiving station B, it will be seen that the impulses transmitted to the distributer D and set up on the selecting relays 93-4- are exactly the same as though each of the positive or marking impulses and each of the negative or spacing impulses of the five-unit characters set up on the five tongues t of the transmitter T had been transmitted over the cable and hence the suppression of the successive current impulses of like sign at the transmitting end has made no change in the resulting signals at the receiving end.

Thus when a positive impulse is transmitted over the cable, the coil of cable relay C R swings its arm ina direction to close a localcir'cuit from battery 40 through the coils 41 of polarized relay L R, causing the armature 42to swing tothe right and connect the battery 43 with the ring R of distributer D. If at this instant the brush B R is passing over segment 1 of ring R at current will flow through the energizing coil of selecting relay 1, which attractsits armature, the latter closing a circuit through a holding coil=on the relay and through a magnet on the translator mechanism which actuates one of the selector disks of the tape printer in the manner well understood. As-

. sequently ofthe samesign and will therefore be su-pln'essed, no signal being sent into the cable.- However, the tongue 42 of the polarized relay L It at the receiving station remains against the right hand contact,

an impulse from thebatte'ry will be transmitted through the ring R andsegment 2 of ring R to energize selecting relay )5. its armature likewise closes a circuit through its holding coil and a magnet of the translator mechanism. i

The next or third impulse of the letter A being negative and of opposite sign, transmitted over the cable, causing the arm of cable relay R to swing over to the other contact, closing a circuit from battery 40 through the coils 45 and causing the armature 42 to swing to thelett against the stop. At this instant the distribnter brush B R on segment 3 and consequently no current will be transmitted to relay r... The next two in1- pulses ofthe letter A being also negative I that my 1 translatormechanism at the receiving sta- :impulscs or character combinations.

constitutes the means suppressing all and of the same sign as the preceding transmitted impulse, will be suppressed at the sending end and no signal will be transmitted to the cable. Accordingly the armature 42 of polarized relay L R'remains against the stop while the brush B It passes over segments 4 and 5 of ring It so that the corresponding selector relays: are not energized.- The result is exactly the same as it a second and a third negative or spacing impulse had been transmitted over the cable. After thehrushes of distributor Df have passed over all of the segments so that the combination of impulses representing character are set up thereon, and as the brushes start again over the rings,the brushesB R nation of fany; particular character have been set up on thetransmitter tongues and have been transmltted to the sending relay.

-The latter, therefore, responds to all of the positive and negative impulses of the di ferent characters and may indicate locally in any suitable manner the passage of these In other words the suppression of impulses of like sign occurs in association with the cable transmitting relay. The condenser Uwhich for suppressing the desired impulses also furnishes a meansot adjusting the length or duration'ot the imiiiulses to correspond with the time required tor a brush to pass over a I 45 distributer. y i y Inasmuch as the resultant eflect upon the tion is the same as it would be it all of the positive and negative impulses of the characters were transmitted over the cable the advantages which accrue trom'my method of successive impulses of like sign and grounding the cable 'at all times a when an impulse is not being transmitted,

will be appreciated by engineers.

I claim fl. In a synchronous telegraph system, the combination of a rotary distributer comprising a commutator, divided into segments anda brush rotatable thereover. means for transmitting to said segments positive and negative charges corresponding to the coinblnat ons ot the telegraph characters, a rea lay connected to said brush and responsive to said charges, and electrosmagnetic transsegment of the mittingfmechanisni having actuating :circuits controlled by said relay and including a condenser the capacity of which is adjustable to determine the duration of thefiow of current in said actuating circuits to correspond with the passage of said brush over one of said commutator segments.

2. In a synchronous telegraph system, an automatic transmitter operating under the control of a code perforated tape and having operating members which receive positive "and negative charges corresponding to the combinations of the telegraph characters, means tortransmittmg said charges in sequence, a relay responsive to said charges,-

and electro-magnetic transmitting mechanism having actuating circuits controlled by said relay and including a condenser the capacity of which is adjustable to determine the duration of the flow of current in any direction.

3. In a telegraph system, a line circuit, sources of oppositely poled current, auto,- matic circuit controlling means "for transmitting a code consisting oi" positive and negative current charges corresponding respectively to the combinations of said code characters, a single relay responsive to all of said charges, and electro responsive means controlled; by said relay operating to transmit to line successive impulses of-opposite sign and to ground said line in substitution of successive repetitions of current impulses of like polarity.

4. In synchronous telegraphsystem, an automatic transmitter having operating meu'ibers which receive positive andnegative charges corresponding to' the combinations of the telegraph characters, means for transmitting said charges in sequence, a single relay responsive to all of said charges, and impressing mechanism controlled by said relay and provided with means for suppressing successive impulses of like sign'orpolarity. p

5. 1h a synchronous telegraph system, an automatic transmitter operating underthe control of a code-perforated tape and having operating members which receive positive and negative charges corresponding to the combinations of the telegraph characters, means for transmitting said charges in sequence, a single relay responsive toall of said charges, and electro-magnetic transmitting' mechanism having actuating circuits controlled by said relay and including condenser the capacity of which determines the flow of currentin any direction. 6. In a synchronous telegraph system, an

automatic transmitting ap iiaratus embodying a condenser having a capacity which determines the flow of current in either direction to the period of one impulse and thereby suppresses successive impulses ot the same sign or polarity,

7. In a synchronous telegraph system wherein the code signals comprise characters composed of different combinations of positive and negative current impulses, each code character having the same number of impulses, an. automatic transmitting apparatus having a single electro-responsive device for receiving a charge corresponding with each of the positive and negative impulses of a code character, and means for suppressing successive impulses of like sign or polarity.

In testimony whereof I affix my signature.

GEORGE n. BENJAMIN. 

